Mrs Foster confirmed in a written answer that permission has not been granted for ground floor office use at the Ballymena advice centre in Church Street run by Ian Paisley and his MLA son Ian Jnr.

The Telegraph revealed last month planning permission had still to be obtained for the conversion of the ground floor from shop to office use.

SDLP MLA John Dallat then tabled an Assembly question, asking Mrs Foster about the planning status of the advice centre and also to detail "any action being taken over non-compliance with planning law in Church Street, Ballymena".

Mrs Foster stated: "Planning Service has confirmed that permission for the use of the ground floor of 9-11 Church Street, Ballymena as an office has not been granted.

"I can also confirm that my department is currently investigating two properties in Church Street, Ballymena for unauthorised changes of use and will progress appropriate action if required."

Mrs Foster's department has declined to identify the two properties being investigated.